Intel GD82559ER, Техническое описание

Страница: 55 / 94

Datasheet 49
Networking Silicon — GD82559ER
7.1.3 PCI Status Register
The 82559ER Status register is used to record status information for PCI bus related events. The
format of this register is shown in the figure below.
Note that bits 21, 22, 26, and 27 are set to 0b and bits 20, 23, and 25 are set to 1b. The PCI Status
register bits are described in the table below.
Figure 19. PCI Status Register
0
Detected Parity Error
Signaled System Error
Received Master Abort
Received Target Abort
Signaled Target Abort
Devsel Timing
Parity Error Detected
Fast Back To Back (target)
C apabilities List
Reserved 0 1 1 0 00 1 0
3 1 3 0 2 9 2 8 2 7 2 6 2 5 2 4 2 3 2 2 2 1 2 0 1 9 1 6
Table 6. PCI Status Register Bits
Bits Name Description
31 Detected Parity Error
This bit indicates whether a parity error is detected. This bit must be
asserted by the device when it detects a parity error, even if parity error
handling is disabled (as controlled by the Parity Error Response bit in the
PCI Command register, bit 6). In the 82559ER, the initial value of the
Detected Parity Error bit is 0b. This bit is set until cleared by writing a 1b.
30 Signaled System Error
This bit indicates when the device has asserted SERR#. In the 82559ER,
the initial value of the Signaled System Error bit is 0b. This bit is set until
cleared by writing a 1b.
29
Received Master
Abort
This bit indicates whether or not a master abort has occurred. This bit must
be set by the master device when its transaction is terminated with a
master abort. In the 82559ER, the initial value of the Received Master
Abort bit is 0b. This bit is set until cleared by writing a 1b.
28 Received Target Abort
This bit indicates that the master has received the target abort. This bit
must be set by the master device when its transaction is terminated by a
target abort. In the 82559ER, the initial value of the Received Target Abort
bit is 0b. This bit is set until cleared by writing a 1b.
27 Signaled Target Abort
This bit indicates whether a transaction was terminated by a target abort.
This bit must be set by the target device when it terminates a transaction
with target abort. In the 82559ER, this bit is always set to 0b.
26:25 DEVSEL# Timing
These two bits indicate the timing of DEVSEL#:
00b - Fast
01b - Medium
10b - Slow
11b - Reserved
In the 82559ER, these bits are always set to 01b, medium.